Add Item to IndexedDB

function addToIndexedDB(databaseName, storeName, item) {
  return new Promise((resolve, reject) => {
    const request = indexedDB.open(databaseName);
 
    request.onupgradeneeded = (event) => {
      const db = event.target.result;
      if (!db.objectStoreNames.contains(storeName)) {
        db.createObjectStore(storeName, { keyPath: "id" });
      }
    };
 
    request.onsuccess = (event) => {
      const db = event.target.result;
      const transaction = db.transaction(storeName, "readwrite");
      const store = transaction.objectStore(storeName);
 
      const addRequest = store.add(item);
 
      addRequest.onsuccess = () => resolve(item); // return item object on success
      addRequest.onerror = () => reject(addRequest.error);
    };
 
    request.onerror = () => reject(request.error);
  });
}

addItemToIndexedDB("myDatabase", "users", { id: 1, name: "John", age: 25 })
  .then(console.log) // { id: 1, name: "John", age: 25 }
  .catch(console.error);